Halloysite-Based Nanomotors with Embedded Palladium Nanoparticles for Selective Benzyl Alcohol Oxidation
Jian Wang, Yan Zhang, Yang Xu, Peiping Zhang, Qian Gao, Qing Liang, Wei Zhang, Wenqing Li, Ruifeng Guo, Bo Jin, Shiding Miao
Abstract
The liquid-phase oxidation benzyl alcohol using hydrogen peroxide (H2O2) as an oxidant is a promising and green strategy for manufacturing aldehydes or/and ketones. Herein palladium (Pd) nanoparticles were impregnated in lumens of halloysite nanotubes by using ionic liquid (1-(2′-hydroxylethyl)-2,3-dimethylimidazolium chloride) as directing agents. On the basis of the asymmetric scroll-like structure of halloysite and the catalytic decomposition ability of Pd toward H2O2, the prepared catalyst (Pd-IL-HNTs) exhibited powerful self-propelled movement at an average speed of 276 ± 35 μm/s in 30.0 wt % H2O2 solution. The specific interaction between nanomotors and benzyl alcohol was observed as a consequence of self-moving behavior and hydrophobic interaction introduced by ionic liquid. With the synergistic coupling of the catalytic ability and powerful movement, Pd-IL-HNTs displayed outstanding catalytic benzyl alcohol oxidation performance. Compared to other nonpropelling catalysts using lamellar clay (montmorillonite and kaolinite) as supports, such HNT-based nanomotors registered superior catalytic performance, and the TOF value of 118.1 h−1 was obtained.